Cutter head for dry shavers



April 9, 1968 E. LISKA 3,376,642

CUTTER HEAD FOR DRY SHAVERS 7 Filed Aug. 24, 1966 2 Sheets-Sheet 1 FIG.

FIG. 3 V F764 ATTORNEYS April 9, 1968 E. LISKA 3,376,642

CUTTER HEAD FOR DRY SHAVERS Filed Aug. 24, 1966 2 Sheets-Sheet 2 IN VENTOR 5/2/0/4 L/SKA,

BY YUNGBLUT, MEL V/LLE,

STKASSER Mos 75/2,

ATTORNEYS United States Patent 3,376,642 CUTTER HEAD FOR DRY SHAVERS Erich Liska, 81 Reiteregg, Hitzendorf, Styria, Austria Filed Aug. 24, 1966, Ser. No. 574,714 3 Claims. (Cl. 30-34651) ABSTRACT OF THE DISCLOSURE This invention relates to a cutter head assembly for use with dry shavers. Specifically, it is concerned with the cutters and the supports therebetween. In the assembly, the cutters are spaced apart and contain aligned openings through which cast support members are received. The latter members are characterized by a major cross-section which exceeds the cross-section of said openings to which the cast members are secured.

This invention relates to a cutter head for dry shavers of the type having lamina-form cutters and at least one cutter support, each of said cutters having at least one cavity, said cutters being arranged adjacent and parallel to each other and being mounted and anchored on each of said cutter supports, each cutter support being in the form of a rod-shaped member and engaging in said cavities in said cutters.

Cutter heads of this kind exhibit an excellent shaving action because it is possible to employ thin hardened steel laminae as cutter blades. It is already known to embed the individual cutters in base plates produced as injection mouldings of metal or plastic, and it is also known to hold the cutters together in position by means of continuous bolt members which are rivited at the ends and by interposing spacers in between the cutters. Also known are cutter heads in which the cutters are pushed into a base plate provided with slots and are fixed by wire pins which pass through all cutters and are pinched inbetween the same. These constructions have the significant defect that they are relatively heavy and consequently require considerable actuating power.

In a known construction the individual cutters are mounted on the supporting elements by deforming the latter. Here the supporting elements consist of bolt members or profiled rods which are pressed flat inbetween the individual cutters. This construction has the defect that, even when complicated clamping and holding devices are employed, the essential accuracy is scarcely attainable and that the forces required for deforming the cutter supports may give rise to a unis-shaping of the cutters or of the entire cutter head, so that the shaving edges of the individual cutters are no longer aligned.

According to the invention, in a cutter head of the above-mentioned kind, the above defects are obviated by arranging that each of the cutter supports is a cast rodform member whose cross-section inbetween the cutters is greater than the cross-section of the cavities in the cutters transversed by the rod members. This arrangement has the particular advantage than thinner laminae may be used as cutter blades because all mechanical stress is avoided during production of the cutter head and that, due to the small volume of the rods it is also possible to employ heavier and low-melting point metals so that the bearing of the mould and of the cutters lies within absolutely permissible limits, whilst finally the weight of the rods acting as cutter supports is considerably less than the weight of base plates and the like.

In the practical execution of the invention, it is of advantage if the cavities in the cutters are rectangular, particularly square, the diameter of the cutter support being preferably equal to the diagonal of the cavity in the 3,376,642 Patented Apr. 9, 1968 cutter. This configuration has the advantage that the rodform cutter supports are non-rotatable with respect to the cutters, so that the shaving head is also rigid against distortion. Advantageously, the cutter support consists of zinc, aluminium, low-melting point alloys or of preferably alcohol-proof plastic, reinforced with wire or the like, particularly of polyamide strengthened with fibre glass or of acetal-polymer strengthened with fibre glass.

In the production of the cutter head according to the present invention, it is preferable to provide the cutters at appropriate spacing in a preferably two-part mould, whereupon, possible after the introduction of the reinforcement, the mould is filled with the material intended for forming the rod-shaped cutter support and possibly supplied under pressure.

A preferred embodiment of the invention for producing a cutter head according to the invention will now be described by way of example, with reference to the accompanying drawing in which:

FIG. 1 is a side elevation of cutter head,

FIG. 2 is a plan view of the cutter head,

FIG. 3 is end elevation of the cutter head,

FIG. 4 illustrates a cutter blade, and

FIGS. 5 and 6 are sections through a casting mould.

The shaving or cutter head shown in FIGS. 1 to 4 consist of several lamina-form cutters 1 which are arranged parallel and adjacent to each other, each of them having at least one square cavity 2 (FIG. 4) but preferably three cavities. These are joined up by cast rod-shaped cutter supports. The diameter of these rods 3 preferably corresponds to the diagonals of the cavities 2 which they traverse. Of course, rods having a cross-section differing from the circular shape may be chosen. Similarly rods of differing diameters may be provided. If need be, the ends of rods 3 protruding from the cutter head may also be connected by terminal flanges, preferably of somewhat half-moon shape.

In the production of the cutter head, the cutters 1 spaced at appropriate distances and with the cavities 2 in alignment, are introduced into a mould and are cast with rods 3 serving as cutter supports, pressure moulding being possibly employed. If the rods 3 are cast from plastics material, such as an alcohol-proof plastic selected from the group consisting of polyamide and acetalpolymer, it is preferable, before proceeding with the moulding operation, to pass a wire through the aligned cavities 2 and to stretch same under tension. Alternatively, cast metallic supports may be provided. Materials found suitable for the practicing of this invention are the low temperature melting metals such as aluminum, zinc and alloys thereof.

FIG. 5 shows a longitudinal section of a two-part mould for producing cutter heads according to the invention, as it appears before the casting operation, whilst FIG. 6 is a section along line VIVI in FIG. 5, but the lefthand half in both figures illustrates the formation of the mould for the injection moulding of plastics, whilst the right-hand half illustrates the formation of the mould for die casting metals but the differences are only slight.

The mould consists of an upper an a lower mould portion 4' and 5, respectively, these being composed of thin plates 6 and 7 which are held between inner end pieces 8 and 9 and outer end pieces 10 and 11, by means of bolts -12 and 13, a cutter 1 being partially surrounded in each case by two adjacent individual parts 6, 8 and 10 or 7, 9 and 11. The upper mould portion 4 is provided with dowels 14 which are insertable in mould portion 5, and with a gate 15 for pouring in the material. The construction of the mould portions for plastics and metals varies chiefly by the difiering shape of the channels 16 and 16', respectively, and by the special formation of the end pieces 8 to 11 of the mould for the injection moulding of plastics, these end pieces having supports for receiving the reinforcement 17, say of hardened steel wire, for the rods The rods 3 may also consist of plastic material filled with fibre glass. Here the plastic material may be filled with glass fibres which are only 1 mm. long and are in the proportion of about 20%.

Suitable materials for the mould are firstly a chrome and tungsten alloy steel exhibiting low dimensional changes (Alloy No. 2419-C 1.05, Mn 0.9, Cr 1.1, W 1.5) and secondly a hot-working chrome and molybdenum alloy steel (Alloy No. 2343- 0.36, Cr 5.0, M0 1.3, V 0.4).

I claim:

1. A cutter head assembly for dry shavers comprising a plurality of lamina-form cutter blades joined together by at least one support member which has been cast therebetween while said blades are held rigid, said cutters being spaced apart and arranged in parallel relationship and containing at least one opening in each of said cutters for receiving said cast support member, whereby said support member is a rod and characterized by a cross-section which exceeds the cross-section of said openlngs.

2. The cutter head assembly claimed in claim 1 where- 4 in said support member is round having a diameter equal to the diagonal of said opening.

3. The cutter head assembly claimed in claim 1 wherein said support member is cast from a low temperature melting alloy selected from the group consisting of zinc and aluminum.

References Cited UNITED STATES PATENTS 2,183,442 12/1939 Blackwell -346.5l X 2,423,595 7/1947 Hall 30346.51 X 3,092,904 6/1963 Bruecker 30-43.92 X r 3,290,781 12/1966 Kratz 30-4392 X 3,178,818 4/ 1965 Liska 30-34651 FOREIGN PATENTS 523,032 7/ 1940 Great Britain. 1,312,898 11/1962 France. 1,026,197 3/ 1958 Germany. 1,312,898 11/1962 France. 1,026,197 3/ 8 Germany. 1,125,311 3/1962 Germany.

MY'RON C. KRUSE, Primary Examiner. 

